Audikast Plus with Sennheiser Momentum 4

Anyone using this combination successfully?
Bought both items specifically to watch TV and noise-cancel the neighbours. Picked the Sennheiser's as they specifically support aptX™ Adaptive, which includes LL

Connects OK, and the APTX light comes on, not the LL light.

Is there a way for forcing the codec to use LL?

Thanks, Mark